1. Field of the Invention
The present invention pertains to apparatus for separating solid materials from mixtures having such solid materials therein. In particular, it pertains to separating apparatus in which the two opposing edges of a wire mesh screen are retained by elongated retainer assemblies against which oppositely directed forces may be applied for placing the screen in tension. Specifically, the present invention pertains to rigid retainer assemblies for use with such separating apparatus.
2. Description of the Prior Art
There are many methods and apparatus for separating solid materials from mixtures having such solid materials therein. In some of these methods, a wire mesh screen is provided for separating the solid materials from dry or wet mixtures containing such solid materials. For example, such screens are frequently used in shale separation and in separating cuttings from drilling muds being circulated in oil and/or gas wells. The wire mesh screen is usually placed in tension and may even be vibrated to aid in the separation process.
Since the wire screen is preferably placed in tension, it is necessary that some means be provided for retaining or holding the edges thereof and placing the screen in tension. For this reason, various types of retainer assemblies have been developed for attachment to opposing edges of the screen. These retainer assemblies may then be engaged by some means for applying forces thereto to place the screen in tension. Since a considerable force may be applied thereto, one of the problems associated with such apparatus is tearing of the screen or separation of the edges thereof from the retainer assemblies.
In recent years, a two-piece retainer assembly has been developed, between the two pieces or members thereof which the edges of the screen are tightly clamped. One of these members may comprise an elongated flat base portion from one edge of which upwardly projects a curved rib portion providing an elongated arcuate convex surface. Another member may also include an elongated base portion from one edge of which upwardly projects a curved rib portion providing an elongated arcuate concave surface. The edge of the screen is sandwiched between the curved rib portions of the respective retainer members for gripping thereby. When forces are applied to the retainer assemblies, the edges of the screen are tightly gripped by the respective retainer members and the screen placed in tension.
Even though the two retainer members and the screen may be welded together by spot welding, it is not uncommon for the screen to tear and disengage the retainer assemblies, or to become so loose therein that tension cannot be retained on the screen. This, of course, reduces the separation efficiency thereof.